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Right of Use Assets - Narrative (Details) $ in Millions | 1 Months Ended | 12 Months Ended
--- | --- | ---
Nov. 30, 2019 contractRenewal | Dec. 31, 2020 CAD ($) | Dec. 31, 2019 CAD ($) | Dec. 31, 2018 CAD ($)
Disclosure of quantitative information about right-of-use assets [line items] |  |  |  |
Contract for transporting natural gas, initial term | 15 years |  |  |
Number of contract renewals | contractRenewal | 8 |  |  |
Renewal period | 24 months |  |  |
Right-of-use assets |  | $ 141 | $ 146 | $ 52
Payments of lease liabilities, classified as financing activities |  | 33 | 25 |
Interest expense on lease liabilities |  | 8 | 4 | 3
Repayments of principal on lease liabilities |  | 25 | 21 |
Expense relating to short-term leases for which recognition exemption has been used |  | 0 | 2 |
Expense relating to leases of low-value assets for which recognition exemption has been used |  | 0 | 1 |
Expense relating to variable lease payments not included in measurement of lease liabilities |  | $ 7 | 6 |
Pioneer Pipeline | Alberta Thermal |  |  |  |
Disclosure of quantitative information about right-of-use assets [line items] |  |  |  |
Proportion of ownership interest in joint operation |  | 50.00% |  |
IFRS 16 |  |  |  |
Disclosure of quantitative information about right-of-use assets [line items] |  |  |  |
Right-of-use assets |  |  |  | $ 85
IFRS 16 | Wind Farms |  |  |  |
Disclosure of quantitative information about right-of-use assets [line items] |  |  |  |
Right-of-use assets |  |  | 31 |
Lease liabilities |  |  | $ 31 |

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- Definition The amount of the expense relating to leases of low-value assets accounted for applying paragraph 6 of IFRS 16. This expense shall not include the expense relating to short-term leases of low-value assets. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 16 -IssueDate 2019-01-01 -Paragraph 53 -Subparagraph d -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=16&code=ifrs-tx-2019-en-r&anchor=para_53_d&doctype=Standard -URIDate 2019-03-27 + Details
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- Definition The amount of the expense relating to short-term leases accounted for applying paragraph 6 of IFRS 16. This expense need not include the expense relating to leases with a lease term of one month or less. Short-term lease is a lease that, at the commencement date, has a lease term of 12 months or less. A lease that contains a purchase option is not a short-term lease. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 16 -IssueDate 2019-01-01 -Paragraph 53 -Subparagraph c -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=16&code=ifrs-tx-2019-en-r&anchor=para_53_c&doctype=Standard -URIDate 2019-03-27 + Details
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- Definition The amount of the expense relating to variable lease payments not included in the measurement of lease liabilities. Variable lease payments are the portion of payments made by a lessee to a lessor for the right to use an underlying asset during the lease term that varies because of changes in facts or circumstances occurring after the commencement date, other than the passage of time. [Refer: Lease liabilities] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 16 -IssueDate 2019-01-01 -Paragraph 53 -Subparagraph e -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=16&code=ifrs-tx-2019-en-r&anchor=para_53_e&doctype=Standard -URIDate 2019-03-27 + Details
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- Definition The amount of assets that represent a lessee's right to use an underlying asset for the lease term. Underlying asset is an asset that is the subject of a lease, for which the right to use that asset has been provided by a lessor to a lessee. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 16 -IssueDate 2019-01-01 -Paragraph 53 -Subparagraph j -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=16&code=ifrs-tx-2019-en-r&anchor=para_53_j&doctype=Standard -URIDate 2019-03-27 + Details
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